The present invention relates to detergent compositions comprising alkanol ethoxylate components of particular description.
Certain alkanol ethoxylates, or simply ethoxylates as the terminology is used herein, are known to the art as materials having principal utilities relating to their surfactant properties. Most commonly, such ethoxylates are employed as components of detergent formulations for use in industry and in the home. Because they have very desirable biodegradation characteristics, market demand for the ethoxylates, now estimated to be about six hundred million pounds per year in the United States, is continually growing.
The general class of alkanol ethoxylate compounds of relevance to the invention is characterized by the chemical formula EQU R--O--CH.sub.2 --CH.sub.2 --O).sub.x H,
wherein R is alkyl and x is an integer greater than or equal to one. Certain ethoxylates within this class are conventionally prepared by the sequential addition of ethylene oxide to the corresponding alkanol (ROH) in the presence of a catalyst.
The most common ethoxylates within this class are the primary alkanol ethoxylates, i.e., compounds of formula I in which the --O--CH.sub.2 --CH.sub.2 --O).sub.x H ether substituent is bound to a primary carbon atom of the alkyl chain R. The present invention, however, more particularly relates to discoveries concerning ethoxylate mixtures comprised in substantial part of secondary alkanol ethoxylates, i.e., compounds of the above formula in which the ether substituent is bound to a secondary carbon atom of the alkyl group.
Secondary alkanol ethoxylates have in the past been commercially prepared by reaction of ethylene oxide with mixtures of secondary alkanols obtained via the oxidation of paraffins. (See, for example, U.S. Pat. No. 3,932,531 and U.S. Pat. No. 2,870,220.) There are suggestions in the art, for instance, U.S. Pat. No. 3,350,462, that secondary alkanols can also be prepared from alpha-olefin mixtures, via sulfation and hydrolysis reactions.
Most particularly, the present invention is directed to novel ethoxylate-containing detergent compositions, wherein the ethoxylate component is characterized by critical definition of the ethoxylate molecules with respect to carbon number of the alkyl chain, number of ethylene oxide adducts in the ether substituent (i.e., the value of x in the above formula), hydrophile-lipophile balance, position of the carbon atom in the alkyl chain to which the ether substituent is bound, and relative content in the composition of compounds having an alkyl group substituted by multiple ether substituents. The prior art is not known to relate critical characterizations in any of these several aspects to the advantageous distinctions now observed between the detergent properties of ethoxylate-containing compositions in accordance with the invention and those of compositions having ethoxylate components of a conventional nature.